In particular also ceramic substrates are known in the most varied versions and are used preferably for electrical power circuits or modules.
In many applications these ceramic substrates are subject to high cyclic temperature loads in which temperature changes in the range between -40.degree. C. and +125.degree. C. can occur throughout.
Due to the different coefficients of thermal expansion of the ceramic layer and metal layer, on the transition between these layers during temperature fluctuations considerable mechanical compressive or tensile stresses occur with a gradient in the ceramic material on the border of the metal layer which is especially large and which leads to cracks in the ceramic layer.
It is known that by structuring of the metal layer, which (the structuring) is very often already dictated by the layout necessary for the circuit, the gradient of tensile and compressive stresses can be reduced.
It has already been suggested (DE 40 04 844) that a structured metal coating be formed by etching techniques, which is weakened in places on its borders to reduce the gradient of tensile and compressive stresses. The teaching imparted in this regard also comprises in its generally held form already known configurations of printed conductors, contact surfaces or similar structured metal coatings and also border weakening as is inevitably obtained in etching of structures of metal coatings and as cannot be avoided.